Telephone-exchange system



APPLICATION FILED JUNE 5,1919.-

Patented Aug. 9, 1921.

UNITED STATESPATENT osmosi HENRY r. GLAUS'EN, or MOUNT VERNON, NEW YORK, ASSIGNOR To WESTERN ELEC- TRIC COMPANY, INCORPORATED, ornnw YORK, N. A CORPORATION ornnw YORK. L

Tnnnrnronn-nxcnmen SYSTEM.,

Specification of Letters raisin. Patented Aug. 9, 1921.

Application filed June 5, 1919. Serial ltd 301,866.

To all whom it may concern:

Be it known that I,-HENRY P. CLAUsEN, a citizen of the United States, residing at Mount Vernon, in the county of Westchester, State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which thefollowing is a full, clear, concise, and exact description.

This invention relates to improvements in telephone exchange systems and has particular reference to a selectively operable switch therefor.

In systems employing machine switching apparatus controlled by impulses impressed upon a telephone circuit by an impulse sending device, and in'which the brushes of a switch are moved directively by said impulses to select a group of trunks and then automatically to hunt an idle trunkin said group, it is possible to manipulatethe impulse sending device to transmit another set' of impulses intended for a succeeding switch before the automatic'trunk hunting operation in the first switch is completed. This results in the mutilation of a call and the probable extension thereof to some other subscribers line than the one desired, with a consequent annoyance to the subscriber and an unnecessary utllization of switches beyond that in which the trouble occurred.

upon the transmission of the first impulse of a second set to said switch, to operate said restoring means and return the switch to normal, where the same will remain during the transmission of succeeding impulses.

The inventive idea involved is capableof receiving a variety of expressions, one of which, for the purpose of illustrating the in vention, is shown in the accompanying drawing; but. it is to be expressly understood that said. drawing is employed merely for the purpose of facilitating the description of the invention as a whole,- and not to define the limits thereof, reference being had to the appended claims for this purpose.

. The drawing illustrates diagrammatically the circuit for a selector switch arranged in accordance with the invention.

It is believed that the invention willbe fully understood from the following de scription of the operation.

Removal of the receiver from its switchhook at substation A will close a circuit to operate line switch B,-which vmay be ofany construction well knowninthe art, to connectbrushes 1, 2 and 3 thereof to terminals a, 5 and 6 of an idle selector switch C. Line relay 7 of the selector switch will then be come'energized' over a circuit traceable from grounded battery, right winding of relay 7, back contact and inner lower armature of cut-off relay 8, terminal 5, brush 2, apparatus of substation A, brush 1, terminal 4,

upper armature and, back contact of cutoff relay 8, and left winding of relay7, to

ground. Relay 7 attracts its armature and establishes a circuit for slow-to-release relay 9 extending from grounded battery,

ing device 11 to transmit a set of impulses to the selector switch corresponding to the first digit of the wantedline.

In responseto .the impulses transmitted, the armature of line relay 7 is vibrated, and upon each retraction thereof a circuit is closed for primary stepping magnet 12 extending from grounded battery, winding of said magnet, winding of slow-to-release relay 13, front contact and right armature; of relay 9, lowermost armature and'back contact of cut-off relay 8, back contact and armature of relay 7 to ground. Magnet 12 energizes in response to each retraction'ofthe armature of relay 7, and steps I the brushes of switch U in their group selecting movement.

Slow-to-release relay 13 is also energized in the circuit traced for magnet 12, and in attracting its armature, establishes a circuit for test relay 14 extending from grounded battery, winding of relay 14, armature and front contact of relay 13, to ground. Relays 9 and 13, being slow to release, maintain their armatures attracted during the transmission of the set of impulses, and at the termination thereof the armature of relay 7 remains attracted thus breaking the circuit for primary stepping magnet 12.

step of the brushes of switch C, conductor 10, 7

front contact and left armature of relay 9 to ground. 9

Release of relay l3 establishes a circuit for secondary stepping magnet 15 extending from grounded battery, winding of said magnet, front contact and left armature thereof, back contact and armature of relay 13, front contact and armature of relay 14, back contact and armature of magnet 15, primary off-normal contact 16, conductor 10, front contact and left armature of relay 9 to ground. Magnet 15 energizes and op.- erates to step the brushes of switch G onto the first set of terminals in the selected group.

Should the switch (not shown) associated with this set of terminals be busy, such condition will be denoted by a ground upon the test terminal 18 thereof, and the locking circuit for test relay 14 will then extend from grounded battery, front contact and armature thereof, brush 17, and test terminal 18 to ground. Magnet 15, being self-interrupt ing, will therefore continue to be operated each time the brush 17 of switch C engages the test terminal of a busy switch, and will step the brushes of switch C until an idle set of terminals in the selected group is found. At such time, magnet 15 and test relay 14, no longer finding ground upon a test terminal leading to the next succeeding switch, will both de'e'nergize and the brushes of selector switch C will rest upon the terminals of said succeeding switch. Release of relay 14 establishes a circuit for cut-oft relay 8 extending from grounded battery, winding of relay 8, back contact and armature of re lay 14, back contact and right armature of magnet 15, off-normal contact 16, conductor 10, front contact and left armature of relay 9, to ground. Relay 8 energizes, and in at-' tracting its upper and inner lower arma tures extends the telephone line to the next succeeding switch, the line and first slowto-release relays of which become energized ceeding switch toground. This latter ground also provides a busy test for the switches now seized, and extends from terminal 1S,brush 17, back contact and right armature of mag net 15, off-normal contact 16, terminal 6 to brush 3, it being understood that relays-7 and 9 deenergized upon the operation of cut-off relay .8, thus removing ground from theleft armature of said relay 9.

Thesubscriber at substation A may now continue to operate the impulse sending de vice 11 towtransmit sets of impulses corre sponding to the remaining digits ofthe called number, to operate succeeding switches until the connection has been established to the wanted line. 7 4 9 At the termination of the conversation the replacing of the receiver upon its switch- 11001; at the'calling and called substations removes ground from test terminal 18 and causes cut-off relay 8 to deenergize. A circuit is then'established for release magnet 19 extending from grounded battery, wind- 7 completed, he had again operated his sending device to transmit the'set of impulses necessary to operate the next succeeding switch; Upon the retraction of the armature of line relay 7, in response to the first im pulse of the second set, a circuit would inimediately be established for release magnet 19, extending from grounded battery, wind-,

ing of said magnet, secondary off-normal v contact 20, lowermost armature and back contact of cut-off relay 8, b'ackcontact and armature of relay 7 to ground. Magnet 19 energizes in this circuit and establishes a locking circuit for itself which extends from grounded battery, winding ofmagnet 19, resistance 21, front contact and armature of magnet 19, front contact and left armature of relay 9, to ground. Magnet 19v operates to returnswitchO to normal. As long as the receiver at substation A is off its switch hook, relays 7 and 9 remain energized, and therefore maintain the locking circuit for release magnet 19 until'the subscriber at substation A abandons the call. It will therefore be apparent that any succeeding impulses transmitted by the operation of the sending device 11 will fail to operate switch G, and said impulses cannot therefore be transmitted to any succeeding switches.

What is claimed is:

1. In a telephone system, a switch for extending a call and having directive and, automatic movements, means for controlling the directive movements of said switch, other means for automatically moving said switch, and means eiiective until the call is abandoned for preventing directive and automatic movements of said switch should the first named means be operated before said other. means has completed its operation.

2. In a telephone exchange system; an incoming line, outgoing lines, a variably operable impulse sending device for transmitting sets of impulses over said incoming line to extend a call, a switch having brushes responsive to one set'of impulses for extending said incoming line to any one of said outgoing lines, and means responsive to another set of impulses transmitted to said switch before the same has seized an outgo ing line for restoring the brushes of the i switch to normal and maintaining the same in such position until the call is abandoned.

3. In a telephonesystem, a switch for extending a call and having primary and secondary movements, means for transmitting impulses to said switch to control its primary movements, means for controlling the secondary movements of said switch, and restoring means for said switch operable, when the first named means is actuated before the second named means has completed its operation, to maintain said switch in its restored condition until the call is abandoned.

4. In a telephone exchange system, an incoming line, outgoing lines, a" variably operable impulse sending device for transmitting sets of impulses over said incoming line to extend a call, a switch having brushes responsive to one set of impulses for extending said incoming line to any one of saidoutgoing lines, and a release magnet responsive to another set of impulses transmitted to said switch before the same has seized an outgoing line for restoring the brushes of the switch to normal and for maintaining the same in such position until the call is abandoned.

5. In a telephone exchange system, an incoming line, outgoing lines, a variably operable impulse sending device for transmitting sets of impulses over said incoming line to extend a call, a switch having brushes resaid restoring means sponsive to one set of impulses for extending said incoming line to any one of said outgoing lines, a line relay for said switch, a release magnet responsive to another set of impulses transmitted to said switch before the same has seized an outgoing line for re storing the brushes of the switch to normal and maintaining the same in such position until the call is abandoned, and a circuit for said release magnet controlled by an armature of said line relay.

6. In a telephone exchange system, an incoming line, outgoing lines, a variably operable impulse sending device for transmitting sets of impulses over said incoming line to extend a call, a switch having brushes responsive to one set of impulses for extending said incoming line to any one of said outgoing lines, a line relay for said switch, a cut-off relay for extending said incoming line to one of said outgoing lines, a release magnet responsive to another set of impulses transmitted to said switch before'the same has seized an outgoing line for restoring the brushes of the switch to normal and for maintaining the same in such position until the call is abandoned. and a circuit for said release magnet controlled through armatures of said line and cut-oil" relays.

7. In a telephone exchange system, an incoming line, groups of outgoing lines, a variably operable impulse sending device for transmitting sets of impulses over said incoming line, a switch having brushes responsive to one set of impulses for extending said incoming line to any one of said outgoing lines, means for controlling said switch to select a group of outgoing lines, means for controlling said switch to hunt an idle line in said group, and restoring means for the brushes of said switch responsive to another series of impulses transmitted to said switch before the same has seized an outgoing line, maintaining said brushes in their restored position during the transmission of further impulses.

8. In a telephone exchange system, a switch, brushes for said switch, means for transmitting a set of impulses to said switch for directively operating said brushes, means for. automatically operating said brushes, and means responsive to another set of impulses transmitted to said switch before the last-named means has completed its operation for placing said switch in a condition from which it cannot be directively or automatically operated.

In witness whereof, I hereunto subscribe my name this 28th day of May, A. D. 191-9.

HENRY P. CLAUSEN. 

